Follistatin is known to be an important regulator of FSH secretion. FS gene expression has been found to be under the regulation of GnRH, gonadal steroids and gonadal peptides. It is unknown whether these hormones alter FS gene expression by alterations in gene transcription. To measure alteration in gene transcription, we have developed an assay quantifying primary transcript production by performing RT-PCR on pituitary RNA. The first aim of this proposal will utilize this assay to quantify changes in FS gene transcription observed through the rat estrous cycle. The second aim of this proposal is to study the regulation of FS gene transcription by GnRH, gonadal steroids and gonadal peptides. We hope that the results of the experiments proposed here will further our understanding of the selective regulation of FSH and reproductive physiology. This information, in turn, may lead to insights into the biology of human fertility.